modules/codec/a52.c

   1 /*****************************************************************************
   2  * a52.c: ATSC A/52 aka AC-3 decoder plugin for VLC.
   3  *   This plugin makes use of liba52 to decode A/52 audio
   4  *   (http://liba52.sf.net/).
   5  *****************************************************************************
   6  * Copyright (C) 2001-2009 VLC authors and VideoLAN
   7  *
   8  * Authors: Gildas Bazin <gbazin@videolan.org>
   9  *          Christophe Massiot <massiot@via.ecp.fr>
  10  *          Thomas Guillem <thomas@gllm.fr>
  11  *
  12  * This program is free software; you can redistribute it and/or modify it
  13  * under the terms of the GNU Lesser General Public License as published by
  14  * the Free Software Foundation; either version 2.1 of the License, or
  15  * (at your option) any later version.
  16  *
  17  * This program is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  20  * GNU Lesser General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU Lesser General Public License
  23  * along with this program; if not, write to the Free Software Foundation,
  24  * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  25  *****************************************************************************/
  26
  27 /*****************************************************************************
  28  * NOTA BENE: this module requires the linking against a library which is
  29  * known to require licensing under the GNU General Public License version 2
  30  * (or later). Therefore, the result of compiling this module will normally
  31  * be subject to the terms of that later license.
  32  *****************************************************************************/
  33
  34 #ifdef HAVE_CONFIG_H
  35 # include "config.h"
  36 #endif
  37
  38 #include <vlc_common.h>
  39 #include <vlc_plugin.h>
  40 #include <vlc_cpu.h>
  41
  42 #include <stdint.h>                                         /* int16_t .. */
  43
  44 #ifdef USE_A52DEC_TREE                                 /* liba52 header file */
  45 #   include "include/a52.h"
  46 #else
  47 #   include "a52dec/a52.h"
  48 #endif
  49
  50 #include <vlc_aout.h>
  51 #include <vlc_block.h>
  52 #include <vlc_codec.h>
  53
  54 static int  Open ( vlc_object_t * );
  55 static void Close( vlc_object_t * );
  56
  57 typedef struct
  58 {
  59     a52_state_t     *p_liba52; /* liba52 internal structure */
  60     bool            b_dynrng; /* see below */
  61     int             i_flags; /* liba52 flags, see a52dec/doc/liba52.txt */
  62     bool            b_dontwarn;
  63     int             i_nb_channels; /* number of float32 per sample */
  64
  65     uint8_t         pi_chan_table[AOUT_CHAN_MAX]; /* channel reordering */
  66     bool            b_synced;
  67 } decoder_sys_t;
  68
  69 #define DYNRNG_TEXT N_("A/52 dynamic range compression")
  70 #define DYNRNG_LONGTEXT N_( \
  71     "Dynamic range compression makes the loud sounds softer, and the soft " \
  72     "sounds louder, so you can more easily listen to the stream in a noisy " \
  73     "environment without disturbing anyone. If you disable the dynamic range "\
  74     "compression the playback will be more adapted to a movie theater or a " \
  75     "listening room.")
  76
  77 vlc_module_begin ()
  78     set_shortname( "A/52" )
  79     set_description( N_("ATSC A/52 (AC-3) audio decoder") )
  80     set_category( CAT_INPUT )
  81     set_subcategory( SUBCAT_INPUT_ACODEC )
  82     add_bool( "a52-dynrng", true, DYNRNG_TEXT, DYNRNG_LONGTEXT, false )
  83     set_capability( "audio decoder", 60 )
  84     set_callbacks( Open, Close )
  85 vlc_module_end ()
  86
  87 /*
  88  * helper function to interleave channels
  89  */
  90 static void Interleave( sample_t *restrict p_out, const sample_t *restrict p_in,
  91                         unsigned i_nb_channels, uint8_t *restrict pi_chan_table )
  92 {
  93     /* We do not only have to interleave, but also reorder the channels */
  94     for( unsigned j = 0; j < i_nb_channels; j++ )
  95     {
  96         for( unsigned i = 0; i < 256; i++ )
  97         {
  98 #ifdef LIBA52_FIXED
  99             union { uint32_t u; int32_t i; } spl;
 100
 101             spl.u = ((uint32_t)p_in[j * 256 + i]) << 4;
 102             p_out[i * i_nb_channels + pi_chan_table[j]] = spl.i;
 103 #else
 104             p_out[i * i_nb_channels + pi_chan_table[j]] = p_in[j * 256 + i];
 105 #endif
 106         }
 107     }
 108 }
 109
 110 /*
 111  * helper function to duplicate a unique channel
 112  */
 113 static void Duplicate( sample_t *restrict p_out, const sample_t *restrict p_in )
 114 {
 115     for( unsigned i = 256; i--; )
 116     {
 117 #ifdef LIBA52_FIXED
 118         union { uint32_t u; int32_t i; } spl;
 119
 120         spl.u = ((uint32_t)*(p_in++)) << 4;
 121         *p_out++ = spl.i;
 122         *p_out++ = spl.i;
 123 #else
 124         sample_t s = *(p_in++);
 125
 126         *p_out++ = s;
 127         *p_out++ = s;
 128 #endif
 129     }
 130 }
 131
 132 static int Decode( decoder_t *p_dec, block_t *p_in_buf )
 133 {
 134     decoder_sys_t *p_sys = p_dec->p_sys;
 135
 136     if (p_in_buf == NULL) /* No drain */
 137         return VLCDEC_SUCCESS;
 138
 139 #ifdef LIBA52_FIXED
 140     sample_t i_sample_level = (1 << 24);
 141 #else
 142     sample_t i_sample_level = 1;
 143 #endif
 144     int i_flags = p_sys->i_flags;
 145     size_t i_bytes_per_block = 256 * p_sys->i_nb_channels * sizeof(sample_t);
 146
 147
 148     /* Every A/52 frame is composed of 6 blocks, each with an output of 256
 149      * samples for each channel. */
 150     block_t *p_out_buf = block_Alloc( 6 * i_bytes_per_block );
 151     if( unlikely(p_out_buf == NULL) )
 152     {
 153         block_Release( p_in_buf );
 154         return VLCDEC_SUCCESS;
 155     }
 156
 157     /* Do the actual decoding now. */
 158     a52_frame( p_sys->p_liba52, p_in_buf->p_buffer,
 159                &i_flags, &i_sample_level, 0 );
 160
 161     if ( (i_flags & A52_CHANNEL_MASK) != (p_sys->i_flags & A52_CHANNEL_MASK)
 162           && !p_sys->b_dontwarn )
 163     {
 164         msg_Warn( p_dec,
 165                   "liba52 couldn't do the requested downmix 0x%x->0x%x",
 166                   p_sys->i_flags  & A52_CHANNEL_MASK,
 167                   i_flags & A52_CHANNEL_MASK );
 168
 169         p_sys->b_dontwarn = 1;
 170     }
 171
 172     if( !p_sys->b_dynrng )
 173     {
 174         a52_dynrng( p_sys->p_liba52, NULL, NULL );
 175     }
 176
 177     for( unsigned i = 0; i < 6; i++ )
 178     {
 179         if( a52_block( p_sys->p_liba52 ) )
 180             msg_Warn( p_dec, "a52_block failed for block %d", i );
 181
 182         sample_t *p_samples = a52_samples( p_sys->p_liba52 );
 183
 184         if ( ((p_sys->i_flags & A52_CHANNEL_MASK) == A52_CHANNEL1
 185                || (p_sys->i_flags & A52_CHANNEL_MASK) == A52_CHANNEL2
 186                || (p_sys->i_flags & A52_CHANNEL_MASK) == A52_MONO)
 187               && (p_dec->fmt_out.audio.i_physical_channels
 188                    & (AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT)) )
 189         {
 190             Duplicate( (sample_t *)(p_out_buf->p_buffer + i * i_bytes_per_block),
 191                        p_samples );
 192         }
 193         else
 194         {
 195             /* Interleave the *$£%ù samples. */
 196             Interleave( (sample_t *)(p_out_buf->p_buffer + i * i_bytes_per_block),
 197                         p_samples, p_sys->i_nb_channels, p_sys->pi_chan_table);
 198         }
 199     }
 200
 201     p_out_buf->i_nb_samples = A52_FRAME_NB; /* 6 * 256 */
 202     p_out_buf->i_dts = p_in_buf->i_dts;
 203     p_out_buf->i_pts = p_in_buf->i_pts;
 204     p_out_buf->i_length = p_in_buf->i_length;
 205     block_Release( p_in_buf );
 206     decoder_QueueAudio( p_dec, p_out_buf );
 207     return VLCDEC_SUCCESS;
 208 }
 209
 210 static int channels_vlc2a52( const audio_format_t *p_audio, int *p_flags )
 211 {
 212     int i_flags = 0;
 213
 214     switch ( p_audio->i_physical_channels & ~AOUT_CHAN_LFE )
 215     {
 216     case AOUT_CHAN_CENTER:
 217         if ( (p_audio->i_physical_channels & AOUT_CHAN_CENTER)
 218               || (p_audio->i_physical_channels
 219                    & (AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT)) )
 220             i_flags = A52_MONO;
 221         else if ( p_audio->i_physical_channels & AOUT_CHAN_LEFT )
 222             i_flags = A52_CHANNEL1;
 223         else
 224             i_flags = A52_CHANNEL2;
 225         break;
 226
 227     case AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT:
 228         if ( p_audio->i_chan_mode & AOUT_CHANMODE_DOLBYSTEREO )
 229             i_flags = A52_DOLBY;
 230         else if ( p_audio->i_chan_mode & AOUT_CHANMODE_DUALMONO )
 231             i_flags = A52_CHANNEL;
 232         else if ( !(p_audio->i_physical_channels & AOUT_CHAN_RIGHT) )
 233             i_flags = A52_CHANNEL1;
 234         else if ( !(p_audio->i_physical_channels & AOUT_CHAN_LEFT) )
 235             i_flags = A52_CHANNEL2;
 236         else
 237             i_flags = A52_STEREO;
 238         break;
 239
 240     case AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_CENTER:
 241         i_flags = A52_3F;
 242         break;
 243
 244     case AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_REARCENTER:
 245         i_flags = A52_2F1R;
 246         break;
 247
 248     case AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_CENTER
 249           | AOUT_CHAN_REARCENTER:
 250         i_flags = A52_3F1R;
 251         break;
 252
 253     case AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT
 254           | AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT:
 255         i_flags = A52_2F2R;
 256         break;
 257
 258     case AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT | AOUT_CHAN_CENTER
 259           | AOUT_CHAN_REARLEFT | AOUT_CHAN_REARRIGHT:
 260         i_flags = A52_3F2R;
 261         break;
 262
 263     default:
 264         return VLC_EGENERIC;
 265     }
 266
 267     if ( p_audio->i_physical_channels & AOUT_CHAN_LFE )
 268         i_flags |= A52_LFE;
 269     *p_flags = i_flags;
 270     return VLC_SUCCESS;
 271 }
 272
 273 static int Open( vlc_object_t *p_this )
 274 {
 275     decoder_t *p_dec = (decoder_t *)p_this;
 276     decoder_sys_t *p_sys;
 277
 278     if( p_dec->fmt_in.i_codec != VLC_CODEC_A52
 279      || p_dec->fmt_in.audio.i_rate == 0
 280      || p_dec->fmt_in.audio.i_physical_channels == 0
 281      || p_dec->fmt_in.audio.i_bytes_per_frame == 0
 282      || p_dec->fmt_in.audio.i_frame_length == 0 )
 283         return VLC_EGENERIC;
 284
 285     /* Allocate the memory needed to store the module's structure */
 286     p_dec->p_sys = p_sys = malloc( sizeof(decoder_sys_t) );
 287     if( p_sys == NULL )
 288         return VLC_ENOMEM;
 289
 290     p_sys->b_dynrng = var_InheritBool( p_this, "a52-dynrng" );
 291     p_sys->b_dontwarn = 0;
 292
 293     p_sys->i_nb_channels = aout_FormatNbChannels( &p_dec->fmt_in.audio );
 294     if( channels_vlc2a52( &p_dec->fmt_in.audio, &p_sys->i_flags )
 295         != VLC_SUCCESS )
 296     {
 297         msg_Warn( p_this, "unknown sample format!" );
 298         free( p_sys );
 299         return VLC_EGENERIC;
 300     }
 301     p_sys->i_flags |= A52_ADJUST_LEVEL;
 302
 303     /* Initialize liba52 */
 304     p_sys->p_liba52 = a52_init( 0 );
 305     if( p_sys->p_liba52 == NULL )
 306     {
 307         msg_Err( p_this, "unable to initialize liba52" );
 308         free( p_sys );
 309         return VLC_EGENERIC;
 310     }
 311
 312     static const uint32_t pi_channels_in[] = {
 313         AOUT_CHAN_LFE, AOUT_CHAN_LEFT, AOUT_CHAN_CENTER, AOUT_CHAN_RIGHT,
 314         AOUT_CHAN_REARLEFT, AOUT_CHAN_REARCENTER, AOUT_CHAN_REARRIGHT, 0
 315     };
 316
 317     aout_CheckChannelReorder( pi_channels_in, NULL,
 318                               p_dec->fmt_in.audio.i_physical_channels,
 319                               p_sys->pi_chan_table );
 320
 321     p_dec->fmt_out.audio = p_dec->fmt_in.audio;
 322 #ifdef LIBA52_FIXED
 323     p_dec->fmt_out.audio.i_format = VLC_CODEC_S32N;
 324 #else
 325     p_dec->fmt_out.audio.i_format = VLC_CODEC_FL32;
 326 #endif
 327     p_dec->fmt_out.i_codec = p_dec->fmt_out.audio.i_format;
 328
 329     aout_FormatPrepare( &p_dec->fmt_out.audio );
 330
 331     if( decoder_UpdateAudioFormat( p_dec ) )
 332     {
 333         Close( p_this );
 334         return VLC_EGENERIC;
 335     }
 336
 337     p_dec->pf_decode = Decode;
 338     p_dec->pf_flush  = NULL;
 339     return VLC_SUCCESS;
 340 }
 341
 342 static void Close( vlc_object_t *p_this )
 343 {
 344     decoder_t *p_dec = (decoder_t *)p_this;
 345     decoder_sys_t *p_sys = p_dec->p_sys;
 346
 347     a52_free( p_sys->p_liba52 );
 348     free( p_sys );
 349 }